/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package com.sun.org.apache.xml.internal.serialize;


import java.io.UnsupportedEncodingException;
import java.util.Hashtable;
import java.util.Locale;

import com.sun.org.apache.xerces.internal.util.EncodingMap;


/**
 * Provides information about encodings. Depends on the Java runtime
 * to provides writers for the different encodings, but can be used
 * to override encoding names and provide the last printable character
 * for each encoding.
 *
 * @author <a href="mailto:arkin@intalio.com">Assaf Arkin</a>
 */
public class Encodings {


  /**
   * The last printable character for unknown encodings.
   */
  static final int DEFAULT_LAST_PRINTABLE = 0x7F;

  // last printable character for Unicode-compatible encodings
  static final int LAST_PRINTABLE_UNICODE = 0xffff;
  // unicode-compliant encodings; can express plane 0
  static final String[] UNICODE_ENCODINGS = {
      "Unicode", "UnicodeBig", "UnicodeLittle", "GB2312", "UTF8", "UTF-16",
  };
  // default (Java) encoding if none supplied:
  static final String DEFAULT_ENCODING = "UTF8";

  // note that the size of this Hashtable
  // is bounded by the number of encodings recognized by EncodingMap;
  // therefore it poses no static mutability risk.
  static Hashtable _encodings = new Hashtable();

  /**
   * @param encoding a MIME charset name, or null.
   */
  static EncodingInfo getEncodingInfo(String encoding, boolean allowJavaNames)
      throws UnsupportedEncodingException {
    EncodingInfo eInfo = null;
    if (encoding == null) {
      if ((eInfo = (EncodingInfo) _encodings.get(DEFAULT_ENCODING)) != null) {
        return eInfo;
      }
      eInfo = new EncodingInfo(EncodingMap.getJava2IANAMapping(DEFAULT_ENCODING), DEFAULT_ENCODING,
          LAST_PRINTABLE_UNICODE);
      _encodings.put(DEFAULT_ENCODING, eInfo);
      return eInfo;
    }
    // need to convert it to upper case:
    encoding = encoding.toUpperCase(Locale.ENGLISH);
    String jName = EncodingMap.getIANA2JavaMapping(encoding);
    if (jName == null) {
      // see if the encoding passed in is a Java encoding name.
      if (allowJavaNames) {
        EncodingInfo.testJavaEncodingName(encoding);
        if ((eInfo = (EncodingInfo) _encodings.get(encoding)) != null) {
          return eInfo;
        }
        // is it known to be unicode-compliant?
        int i = 0;
        for (; i < UNICODE_ENCODINGS.length; i++) {
          if (UNICODE_ENCODINGS[i].equalsIgnoreCase(encoding)) {
            eInfo = new EncodingInfo(EncodingMap.getJava2IANAMapping(encoding), encoding,
                LAST_PRINTABLE_UNICODE);
            break;
          }
        }
        if (i == UNICODE_ENCODINGS.length) {
          eInfo = new EncodingInfo(EncodingMap.getJava2IANAMapping(encoding), encoding,
              DEFAULT_LAST_PRINTABLE);
        }
        _encodings.put(encoding, eInfo);
        return eInfo;
      } else {
        throw new UnsupportedEncodingException(encoding);
      }
    }
    if ((eInfo = (EncodingInfo) _encodings.get(jName)) != null) {
      return eInfo;
    }
    // have to create one...
    // is it known to be unicode-compliant?
    int i = 0;
    for (; i < UNICODE_ENCODINGS.length; i++) {
      if (UNICODE_ENCODINGS[i].equalsIgnoreCase(jName)) {
        eInfo = new EncodingInfo(encoding, jName, LAST_PRINTABLE_UNICODE);
        break;
      }
    }
    if (i == UNICODE_ENCODINGS.length) {
      eInfo = new EncodingInfo(encoding, jName, DEFAULT_LAST_PRINTABLE);
    }
    _encodings.put(jName, eInfo);
    return eInfo;
  }

  static final String JIS_DANGER_CHARS
      = "\\\u007e\u007f\u00a2\u00a3\u00a5\u00ac"
      + "\u2014\u2015\u2016\u2026\u203e\u203e\u2225\u222f\u301c"
      + "\uff3c\uff5e\uffe0\uffe1\uffe2\uffe3";

}
